<template>
    <div class="grid grid-cols-2 h-screen">
        <div class="col-span-2 order-2 md:col-span-1 md:order-1 bg-white  dark:bg-gray-800">
        	<!-- 指定为 flex 布局，并设置为屏幕垂直水平居中，高度为 100% -->
            <div class="flex justify-center items-center h-full flex-col animate__animated animate__bounceInLeft animate__fast">
                <h2 class="font-bold text-4xl mb-7 text-blue-700 dark:text-white">Weblog 博客登录</h2>
                <p class="text-blue-700 dark:text-white">一款由 Spring Boot + Mybaits Plus + Vue 3.2 + Vite 4 开发的前后端分离博客。</p>
                <!-- 指定图片宽度为父级元素的 1/2 -->
                <img src="@/assets/developer.png" class="w-1/2">
            </div>
        </div>
        <div class="flex flex-col col-span-2 order-1 md:col-span-1 md:order-2 bg-white  dark:bg-gray-800">
            <!-- 白天黑夜开关，ml-auto 靠右显示 -->
            <label class="switch ml-auto mt-4 mr-4">
                <input type="checkbox" v-model="isLight" @click="toggleDark()">
                <span class="slider"></span>
            </label>

            <!-- flex-col 用于指定子元素垂直排列 -->
            <div class="flex justify-center items-center h-full flex-col animate__animated animate__bounceInRight animate__fast">
                <!-- 大标题，设置字体粗细、大小、下边距 -->
                <h1 class="font-bold text-4xl mb-5 dark:text-white">欢迎回来</h1>
                <!-- 设置flex布局，内容垂直水平居中，文字颜色，以及子内容水平方向x轴间距 -->
                <div class="flex items-center justify-center mb-7 text-gray-400 space-x-2 dark:text-gray-500">
                    <!-- 左边横线，高度为1px，宽度为16，背景色设置 -->
                    <span class="h-[1px] w-16 bg-gray-200 dark:bg-gray-700"></span>
                    <span>账号密码登录</span>
                    <!-- 右边横线 -->
                    <span class="h-[1px] w-16 bg-gray-200 dark:bg-gray-700"></span>
                </div>
                <!-- 引入 Element Plus表单组件，移动端设置宽度为 5/6，PC端设置为 2/5 -->
                <el-form class="w-5/6 md:w-2/5" ref="formRef" :rules="rules" :model="form">
                    <el-form-item prop="username">
                        <!-- 输入框组件 -->
                        <el-input size="large" v-model="form.username" placeholder="请输入用户名" :prefix-icon="User" clearable/>
                    </el-form-item>
                    <el-form-item prop="password">
                        <!-- 密码框组件 -->
                        <el-input size="large" type="password" v-model="form.password" placeholder="请输入用户密码" :prefix-icon="Lock" clearable show-password/>
                    </el-form-item>
                    <el-form-item>
                        <!-- 登录按钮，宽度设置为100% -->
                        <el-button class="w-full mt-2" size="large" :loading="loading" type="primary" @click="onSubmit">登录</el-button>
                    </el-form-item>
                </el-form>

            </div>
        </div>
    </div>
</template>

<script setup>
    // 引入 Element Plus中的用户、锁图标
    import { User, Lock } from '@element-plus/icons-vue';
    import { login } from '@/api/admin/user';
    import { ref, reactive, onMounted, onBeforeUnmount } from 'vue';
    import { showMessage } from '@/composables/util';
    import { setToken } from '@/composables/cookie';
    import { useUserStore } from '@/stores/user';
    import { useDark, useToggle } from '@vueuse/core'
    import router from '@/router';    
    // 导入 element-plus 暗黑 css
    import 'element-plus/theme-chalk/dark/css-vars.css'

    // 定义响应式的表单对象
    const form = reactive({
        username: '',
        password: ''
    })

    // 登录按钮加载
    const loading = ref(false)

    // 表单引用
    const formRef = ref(null)

    const userStore = useUserStore()

    // 是否是白天
    const isLight = ref(true)
    const isDark = useDark({
        onChanged(dark) {
            // update the dom, call the API or something
            console.log('onchange:' + dark)
            if (dark) {
                // 给 body 添加 class="dark"
                document.documentElement.classList.add('dark');
                // 设置 switch 的值
                isLight.value = false;
            } else {
                // 移除 body 中添加 class="dark"
                document.documentElement.classList.remove('dark');
                isLight.value = true
            }
        },
    })
    const toggleDark = useToggle(isDark)

    // 表单验证规则
    const rules = {
        username: [
            {
                required: true,
                message: '用户名不能为空',
                trigger: 'blur',
            }
        ],
        password: [
            {
                required: true,
                message: '密码不能为空',
                trigger: 'blue',
            }
        ],
    }

    // 登录
    const onSubmit = () => {
        // 先验证form表单字段
        formRef.value.validate((valid) => {
            if (!valid) {
                console.log("表单验证不通过");
                return false
            }

            // 开始加载
            loading.value = true

            // 调用登录接口
            login(form.username, form.password).then((res) => {
                console.log(res);
                // 判断是否成功
                if (res.success == true) {
                    // 提示登录成功    
                    showMessage('登录成功')

                    // 存储Token到Cookie中
                    let token = res.data.token
                    setToken(token)

                    // 获取用户信息，并存储到全局状态中
                    userStore.setUserInfo()

                    // 跳转到后台首页
                    router.push('/admin/index')
                } else {
                    // 获取服务端返回的错误信息
                    let message = res.message;
                    console.log(message)
                    // 提示信息
                    showMessage(message, 'error')
                }
            })
            .finally(() => {
                // 结束加载
                loading.value = false
            })
        })
        
    }

    // 按回车键后，执行登录事件
    function onKeyUp(e) {
        if (e.key == 'Enter') {
            onSubmit()
        }
    }

    // 添加键盘监听
    onMounted(() => {
        document.addEventListener('keyup', onKeyUp)
    })

    // 移除键盘监听
    onBeforeUnmount(() => {
        document.removeEventListener('keyup', onKeyUp)
    })

</script>

<style scoped>
/* The switch - the box around the slider */
.switch {
  font-size: 14px;
  position: relative;
  display: inline-block;
  width: 3.5em;
  height: 2em;
}

/* Hide default HTML checkbox */
.switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

/* The slider */
.slider {
  --background: #28096b;
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--background);
  transition: .5s;
  border-radius: 30px;
}

.slider:before {
  position: absolute;
  content: "";
  height: 1.4em;
  width: 1.4em;
  border-radius: 50%;
  left: 10%;
  bottom: 15%;
  box-shadow: inset 8px -4px 0px 0px #fff000;
  background: var(--background);
  transition: .5s;
}

input:checked + .slider {
  background-color: #522ba7;
}

input:checked + .slider:before {
  transform: translateX(100%);
  box-shadow: inset 15px -4px 0px 15px #fff000;
}
</style>